Thrombocytopenia
Thrombocytopenia is a condition in which the blood has a lower-than-normal number of platelets. Platelets are small cell fragments that help the blood clot. When platelet counts are very low, abnormal bleeding can occur.
Causes include bone marrow disorders, certain medications, autoimmune conditions such as immune thrombocytopenia (ITP), viral infections and liver disease.
Mild thrombocytopenia may cause no symptoms. When symptoms occur, they can include easy bruising, prolonged bleeding from cuts, nosebleeds, blood in the urine or stool, and small purple or red spots on the skin (petechiae).
A full blood count revealing a low platelet count or abnormal mean platelet volume prompts further investigation to identify the underlying cause.
Causes of Thrombocytopenia
Thrombocytopenia can result from reduced platelet production, increased platelet destruction, or sequestration of platelets in an enlarged spleen.
Reduced production:
- Bone marrow disorders such as leukaemia, myelodysplastic syndromes and aplastic anaemia
- Chemotherapy or radiotherapy
- Severe vitamin B12 or folate deficiency
- Viral infections such as HIV and hepatitis C
Increased destruction:
- Immune thrombocytopenia (ITP), in which the immune system attacks platelets
- Medications including heparin (heparin-induced thrombocytopenia), certain antibiotics and anticonvulsants
- Disseminated intravascular coagulation (DIC)
- Thrombotic thrombocytopenic purpura (TTP)
Sequestration:
- Liver cirrhosis with portal hypertension, which causes the spleen to enlarge and trap platelets
Tests that can help check this condition
Learn more on the official NHS page .
Medical review
Dr. Shahzaib Ahmad MBBS, BSc, MRCP, FRCA, FFICM
Clinical Supervisor - Vitall|GMC 7495062|Profile
Reviewed on 22/05/2026
Next review due 22/05/2027
Review focus: Blood biomarkers, laboratory testing methodology, and biochemical interpretation.
